Red Algae: High Bioavailability Of Calcium

The red algae called Lithothamnium calcareum contains a particularly large amount of bioavailable calcium and is therefore very suitable as a natural calcium supplement. In addition, the red algae contain many other minerals and thus compete with the Sango sea coral. Here you can find out how the two natural sources of calcium differ and what needs to be considered when taking them.

The red algae with a lot of calcium

Lithothamnium calcareum (also called Phymatolithon calcareum) is a red alga, also known as “calcareous alga”, “red lime alga” or “calcium alga”. It belongs to the seaweed family and was long mistaken for a coral because of its red-purple color.

The red algae L. calcareum is considered a high-quality natural source of calcium because, in addition to minerals such as magnesium, iron, zinc, and iodine, it accumulates large amounts of calcium from the sea. The red algae are therefore used for dietary supplements (also represents a good alternative to the Sango sea coral) or added to plant-based milk (e.g. soy, oat, or rice drinks) in order to increase their calcium content so that it usually reaches 120 mg Calcium per 100 g is the same as in cow’s milk.

However, according to a ruling by the European Court of Justice in April 2021, organic plant drinks were no longer allowed to be enriched with L. calcareum because the red algae were not available in organic quality. But that has now changed again, as Natumi, manufacturer of high-quality plant drinks, informed us on request (as of June 2, 2022). Because there are now certified organic versions of this algae calcium-enriched organic plant drinks will soon be available again, or in some cases already.

Harvesting and processing of the red algae

L. calcareum grows 20 to 50 meters deep on the Atlantic and Mediterranean coasts. When the alga dies, it sinks to the bottom of the sea and settles there in ditches, from where it is then harvested within three months or sucked off using special devices.

Such an environmentally friendly harvest is necessary because the red algae are characterized by their particularly slow growth – it only grows a few centimeters per year. After harvesting, the red seaweed is gently dried, crushed, and finally ground into powder.

Functions of calcium

Calcium is a very important mineral, so you should always make sure you have a good and sufficient supply. In the human organism, calcium has e.g. the following tasks:

  • Production and secretion of hormones and enzymes
  • Structure of bones and teeth
  • the function of muscles and nerves
  • Regulation of the acid-base balance

Identify and correct calcium deficiency

A calcium deficiency can have a variety of causes and manifest itself in symptoms such as dry skin, circulatory problems, brittle nails, hair loss, sleep disorders, etc. – symptoms that can also have many other causes. It is therefore not easy to identify a calcium deficiency.

If it turns out that you need to optimize your calcium supply, you can do this through your diet (here you will find the best plant-based sources of calcium) or you can also take a dietary supplement with calcium. In addition to L. calcareum, the natural calcium-rich food supplements also include the Sango sea coral.

Red algae L. calcareum and Sango sea coral – the difference

The Sango sea coral is an excellent source of calcium. You can read all about its effects and properties under the previous link. Since the Sango sea coral is obtained in Japan, many people do not feel comfortable taking it because of potential radioactive contamination (Fukushima) (although at least the Sango products of effective nature are regularly checked in radioactivity analyses and corresponding contamination could never be determined ).

An alternative to the Sango sea coral in terms of calcium supply is the red algae Lithothamnium calcareum. Calcium and magnesium are not in such a good ratio as in the Sango sea coral – there the ratio is about 2:1 (Ca: Mg) and in red algae about 5:1. However, if you need magnesium as well as calcium, you can improve the ratio by supplementing with magnesium.

For example, if you take red algae at a dose of 2.4 g per day, you could also take at least 120 mg of magnesium to achieve the optimal ratio of 2:1.

The advantage of taking it separately is that you can also take more magnesium if needed, which is not the case with Sango Sea Coral, as otherwise, you would be consuming too much calcium. Another advantage is that you can choose the magnesium preparation that suits you individually (e.g. magnesium citrate, malate, orotate, etc.), so you are not dependent on the magnesium carbonate in Sango.

If you only need calcium because your diet is low in calcium but also provides enough magnesium (which is often the case with plant-based diets), then calcium algae preparations are perfect for you.

High bioavailability of calcium

If a dietary supplement or food contains particularly high amounts of a mineral, this does not mean that this large amount can actually be absorbed in the intestine and used by the body. In this context, one speaks of bioavailability. This tells you how much of a substance is absorbed by the body and how much of it is simply excreted (with urine or stool). Calcium is primarily absorbed through the small intestine.

From the intestine, the mineral enters the blood, from where it is distributed throughout the body. About 99% of the calcium is stored in the bones and teeth. Excess calcium is excreted in the urine.

In the red algae L. calcareum, 80% of calcium is present as calcium carbonate. Calcium carbonate is calcium that is bound to the salt of carbonic acid (carbonate). Calcium is absorbed by the body in relatively high amounts in the form of calcium carbonate. However, the source of the calcium carbonate matters (12). Because calcium carbonate from natural sources (such as Lithothamnium calcareum or Sango sea coral) has been shown in studies to have a higher bioavailability than artificial calcium carbonate.

The red algae also performed better in comparison to other natural sources of calcium carbonate: while the bioavailability of calcium carbonate from minerals was around 70% and that of calcium carbonate from oyster shells was 27%, the calcium carbonate from the calcium algae had a bioavailability of around 87 %.

More iodine in the red algae than in the Sango sea coral

Like other seaweed, the calcium-rich red algae is a very good source of iodine. Compared to algae such as hijiki, arame, and kelp, which can contain extremely high levels of iodine, the iodine content in Lithothamnium calcareum is just about right. 1 g L. calcareum contains around 34 µg iodine – the daily requirement is 200 µg. Assuming a dose of 2.4 g L. calcareum per day, you would ingest 85 µg iodine – the perfect dose to optimize the iodine supply. However, since the mineral content of algae can vary greatly, you should only choose Calcareum preparations where the iodine content is regularly measured and reported.

Iodine is an essential trace element that the thyroid gland in particular needs to fulfill its tasks. The thyroid needs iodine to produce hormones. Iodine is also used for energy metabolism, the nervous system, and the skin.

However, the daily iodine requirement should not be exceeded, because too much iodine could (just like an iodine deficiency) lead to hypothyroidism. People with Hashimoto’s thyroiditis in particular should not take too much iodine, as this could accelerate the disease. If you suffer from a thyroid problem, you should take the Sango sea coral because of the potentially high iodine content in L. calcareum – it only contains 7 µg iodine per gram (at least the products of effective nature ). Red seaweed, on the other hand, works well for people who need a little extra iodine.

The red alga is a good alternative to the Sango sea coral

In summary, the red algae L. calcareum is a good alternative to the Sango sea coral. It is a high-quality natural source of calcium, which, like the Sango sea coral, provides many other minerals. In contrast to the Sango sea coral, L. calcareum even contains these minerals in relevant amounts – for the Sango coral, this only applies to calcium and magnesium. In addition, calcium algae are characterized by their high bioavailability. When taking it, attention should be paid to the iodine content and (if necessary) the additional supply of magnesium.

Heavy metal pollution in the red alga L. calcareum

However, the red algae not only stores minerals that are valuable for humans but also heavy metals. So, are Lithothamnium calcareum products potentially harmful? Studies have taken a closer look at the heavy metal burden of L. calcareum from Ireland, Italy, and Brazil.

No critical values were found for cadmium, arsenic, mercury, and uranium. The maximum levels that are tolerable according to the Federal Institute for Risk Assessment are therefore not exceeded with a daily dose of 2.4 g. For mercury, the measurements were even well below the permitted mercury content in fish – a food of which much larger amounts are eaten (several 100 g per week) than of calcium algae (max. 16.8 g per week).

Aluminum in the red algae

According to an analysis by L. calcareum from Italy, the algae contain higher amounts of aluminum than other red algae and also than brown and green algae. The Italian seaweed contained up to 8750 mg aluminum per kg, which is actually a very high value.

However, the region of origin seems to make a big difference in the aluminum content, as the aluminum content of L. calcareum from Ireland was only 291 mg/kg, and that of algae from Brazil was 650 mg/kg.

According to the Federal Institute for Risk Assessment, the weekly aluminum intake should not exceed 1 to 2 mg per kg of body weight. If you calculate the above aluminum values ​​down to the typical daily red algae dose of 2.4 g, you would arrive at the following aluminum values ​​per week:

  • L. calcareum from Ireland: 4.9 mg
  • L. calcareum from Brazil: 11 mg
  • L. calcareum from Italy: 147 mg

According to the BfR, a person who weighs 70 kg could take between 70 and 140 mg of aluminum per week throughout their life without having to fear any health risks. While the algae from Ireland and Brazil are far below these values, the value for Italian L. calcareum exceeds the BfR recommendation.

Pay attention to the origin of the red algae

From the above measurements of the aluminum content, it can be concluded that when taking L. calcareum, attention should be paid to the origin of the red algae. As a rule, the origin of the algae is indicated on the packaging. Prefer L. calcareum from Brazil or Ireland, or contact the manufacturer for an up-to-date analysis of aluminum content.

In our article Eliminate aluminum, we present measures to prevent aluminum from being stored in the body.

The side effects of the red algae L. calcareum

It has long been known that the intake of calcium carbonate requires sufficient gastric acid since calcium carbonate neutralizes gastric acid. A study on rats confirmed that the red algae L. calcareum significantly increases gastric pH. This is an advantage for people who produce too much stomach acid and therefore suffer from heartburn, for example.

Since the capsules or the powder with the red algae are not taken with the meal, but 30 minutes beforehand, the algae will not have a disruptive effect on digestion or gastric acid formation, even in people with a lack of stomach acid. It would be different if you took the algae preparations with food.

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